William Kempf carefully considered the originally proposed interface and
suggested the new interface which is currently used. He also started and
fueled the discussion about the analogy optional<>/smart pointer and
about relational operators.

Peter Dimov, Joel de Guzman, David Abrahams, Tanton Gibbs and Ian Hanson
focused on the relational semantics of optional (originally undefined); concluding
with the fact that the pointer-like interface doesn't make it a pointer so
it shall have deep relational operators.

Augustus Saunders also explored the different relational semantics between
optional<> and a pointer and developed the OptionalPointee concept
as an aid against potential conflicts on generic code.

Joel de Guzman noticed that optional<> can be seen as an API on top
of variant<T,nil_t>.

Dave Gomboc explained the meaning and usage of the Haskell analog to optional<>:
the Maybe type constructor (analogy originally pointed out by David Sankel).